So as we all know the intake air temps get low enough in winter to hinder fuel economy and idle combustion efficiency. I have a winter front the helps out quite a bit, but I think they could stand being a little warmer.

I generally block off my home depot CAI in winter to keep snow/moisture from entering the airbox and maybe run a little warmer air.

I have been considering adding a 2" deck plate on the engine side of the air box. Close it in the summer when I don't want engine air, and open it in the winter when it's a good thing.

I considered a 3" opening because my HD CAI is 3" and the plug would work for both, but not sure I want/need that much hot engine bay air?

What do you guys think?

--- Update to the previous post...

Something like this.

There is more to warm air for mileage than just IAT's.The warm air is less dense, so it takes less hp to move thru it. Same thing with warm tires, warm gear lubes, etc. Warmer IAT's do seem to help, but without a resistor setup like Michael was using on a rheostat it's really hard to quantify what gains are from IAT's and what gains are from the warm air's effect on the truck.